Faeries Aire and Death Waltz (The 4th frame) is a Classical recomposition of U.N. Owen was her (Death Waltz), spliced with another song. Faeries Aire and Death Waltz has never been played by human nor machine, because it's impossible to do so.

All of you are idiots. Such "Faeries Aire and Death Waltz" is a joke song by John Stump. The name of this song is commonly tagged on the theme of the secret boss from Touhou 6, where the song is called 'U.N. Owen was Her?.'

Because the Musical score is gibberish. There are too many notes that are both impossible to play, and several of these notes played at the same time by the same instrument. It's no longer music, it's just a mess.

I listened to it, still just death waltz. The Video is mislabeled. And it's not that the notes are too complex it's that the notes don't make sense. The notes are quite literally impossible. That musical score isn't music: it's gibberish. What you're saying is like asking someone to pronounce "ufujbouisfskbfgiousghiksagvysliagujsbgdflkiasugh" as easy as breathing because it uses the English Alphabet.